The concept of resonance is of fundamental importance in the field of antennas. More specifically, for resonant antennas, the size of the antenna can be directly related to the wavelength of the electromagnetic wave it is designed to detect, so that incident signals at the antenna benefit from a resonance condition which effectively provides amplification and allows easier readout with appropriate electronics. The resonance condition can substantially limit the frequency range over which an antenna can optimally perform. Small electric antennas that operate at lower frequencies can experience a loss in sensitivity when the wavelength of the incoming signal is large when compared to the conductive structures of the antenna, which can provide a weak resonant response. One limited solution for higher frequencies can be to use semiconductors and/or superconductors as electromagnetic radiation detectors that can detect photons and/or actively interact with the electromagnetic field eliminating the need to exploit the resonance condition. However, semiconductors and superconductors can have an intrinsic limit of operation at very high frequencies due to materials properties. The large size antennas at lower frequencies can limit their use for a variety of applications where available space is an issue.
SQUID arrays have been proposed in the prior art for utilization as radio frequency magnetic field detectors and as low noise amplifiers for existing primary antenna structures. These arrays of SQUIDs, which can be connected in a plurality of ways, are also known as Superconducting Quantum Interference Filters (SQIFs). Arrays consisting of the Josephson junctions, or any other arrays based on superconductivity that provide constructive interference patterns between the elements, either SQIFs or individual Josephson junctions, can also be utilized. However, there is no obvious way to provide a seamless solution for a system consisting of a SQIF chip (i.e., a SQUID array) with unique characteristics in conjunction with supporting structures that allows obtaining a calibrated transfer function for the broadband information carried by the free space electromagnetic waves. There is a need for a system of systems that can use of SQUID arrays as a far-field and near-field RF radiation detector with unique antenna characteristics, such as frequency, power, and temperature controls. Such a system could extend the concept of quantum detection of semiconductor devices to the entire frequency range of the electromagnetic spectrum, but satisfying all these requirements together in one device can be especially intricate.
In view of the above, it can be an object of the present invention to provide a size independent antenna for broadband detection of RF radiation without loss of sensitivity based on the detection of the energy present in the magnetic component of the incoming electromagnetic wave. Another object of the present invention can be to provide a SQIF antenna that both detects and amplifies incoming RF energy and converts that energy into a usable signal. Still another object of the present invention can be to provide a SQUID array antenna that does not require a dish or feed structure in order to detect incoming RF signals. Another object of the present invention can be to provide structures to help manage in ways other than to concentrate the electromagnetic energy, including DC magnetic field, in order to optimize the transfer function characteristics of the device in practice. Another object of the present invention can be to provide a three-dimensional (3D) SQUID array circuit or a three dimensional configuration of two dimensional squid arrays and/or any combination to account for the three axes of space. Still another object of the present invention can be to provide a size independent antenna for broadband detection of RF radiation that can be consistently fabricated in a cost-effective manner.